Ann M. Brearley

Time-resolved spectroscopic measurements on microscopic solvation dynamics

This paper reinvestigates the use of transient fluorescence spectroscopy of polar aromatics in solution as a method to determine microscopic solvation dynamics. It is shown that the compounds previously employed as polar fluorescent probes tend to fall into three photophysical classes depending upon: (i) whether the photon induced change in μ occurs simultaneously with photon absorption (ii) whether solvent motion subsequent to photon absorption is required to induce the change in μ; or (iii) whether two excited‐state isomers with different μ’s are present simultaneously. The consequence of the different classes on microscopic solvation dynamic measurements is discussed with a molecular example for each class: (i) 4‐aminophthalimide, (ii) 4‐(9‐anthryl)‐N, N‐dimethylaniline, and (iii) bianthryl, respectively. In addition, we introduce a new transient fluorescence procedure for the determination of solvation dynamics that has advantages over the traditional transient Stokes‐shift method. Finally, for the fi...

Novel Polymorphisms Associated with Tacrolimus Trough Concentrations: Results from a Multicenter Kidney Transplant Consortium

Background. The CYP4503A5*1 genotype is associated with lower tacrolimus concentrations. Although its effect is important, it incompletely explains the variability in tacrolimus concentrations and has a relatively low minor allele frequency in whites relative to African Americans (AA). Methods. We studied clinical and recipient genetic correlates of dose-normalized tacrolimus troughs (n=12,277) in the first 6 months posttransplant using a customized single-nucleotide polymorphism chip with 2722 variants in a large, ethnically diverse (144 AA and 551 non-AA) adult kidney transplant population through a seven-center consortium. Results. During the 6-month study, AAs had consistently lower median (interquartile range) troughs than non-AAs, 6.2 (4.4–8.4) ng/mL vs. 8.3 (6.4–10.4) ng/mL (P<0.0001), despite 60% higher daily doses, 8 (5–10) mg vs. 5 (4–7) mg (P<0.0001). The median tacrolimus trough concentration in week 1 posttransplant was particularly low in AAs (2.1 [1.2–3.5] ng/mL) compared with non-AAs (5.0 [3.1–8.2] ng/mL) (P<0.0001), despite similar initial doses. In single-variant analysis, CYP3A5*3 (rs776746) was the top variant (P=2.4×10−33) associated with troughs. After adjustment for CYP3A5*3, clinical factors and race, 35 additional variants were identified (P<0.01, not significant at false discovery rate 20%). In the final multivariant, regression models beginning with these variants and clinical factors, seven variants were identified in the non-AA and seven variants in the AA group towards the first trough concentrations. Rs776746 (CYP3A5), rs2239393 (COMT) and diabetes were the only factors common in both populations. Conclusion. We identified variants beyond CYP3A5*3, which may further explain pharmacokinetic variability of tacrolimus and demonstrated that important variants differ by race.

Psychosocial Distress and Stroke Risk in Older Adults

Background and Purpose— To investigate the association of psychosocial distress with risk of stroke mortality and incident stroke in older adults. Methods— Data were from the Chicago Health and Aging Project, a longitudinal population-based study conducted in 3 contiguous neighborhoods on the south side of Chicago, IL. Participants were community-dwelling black and non-Hispanic white adults, aged 65 years and older (n=4120 for stroke mortality; n=2649 for incident stroke). Psychosocial distress was an analytically derived composite measure of depressive symptoms, perceived stress, neuroticism, and life dissatisfaction. Cox proportional hazards models examined the association of distress with stroke mortality and incident stroke over 6 years of follow-up. Results— Stroke deaths (151) and 452 incident strokes were identified. Adjusting for age, race, and sex, the hazard ratio (HR) for each 1-SD increase in distress was 1.47 (95% confidence interval [CI]=1.28–1.70) for stroke mortality and 1.18 (95% CI=1.07–1.30) for incident stroke. Associations were reduced after adjustment for stroke risk factors and remained significant for stroke mortality (HR=1.29; 95% CI=1.10–1.52) but not for incident stroke (HR=1.09; 95% CI=0.98–1.21). Secondary analyses of stroke subtypes showed that distress was strongly related to incident hemorrhagic strokes (HR=1.70; 95% CI=1.28–2.25) but not ischemic strokes (HR=1.02; 95% CI=0.91–1.15) in fully adjusted models. Conclusions— Increasing levels of psychosocial distress are related to excess risk of both fatal and nonfatal stroke in older black and white adults. Additional research is needed to examine pathways linking psychosocial distress to cerebrovascular disease risk.

Choline supplementation in children with fetal alcohol spectrum disorders: a randomized, double-blind, placebo-controlled trial

BACKGROUND Fetal alcohol spectrum disorders (FASDs) are conditions characterized by physical anomalies, neurodevelopmental abnormalities, and neurocognitive deficits, including intellectual, executive, and memory deficits. There are no specific biological treatments for FASDs, but rodent models have shown that prenatal or postnatal choline supplementation reduces cognitive and behavioral deficits. Potential mechanisms include phospholipid production for axonal growth and myelination, acetylcholine enhancement, and epigenetic effects. OBJECTIVE Our primary goal was to determine whether postnatal choline supplementation has the potential to improve neurocognitive functioning, particularly hippocampal-dependent memory, in children with FASDs. DESIGN The study was a double-blind, randomized, placebo-controlled pilot trial in children (aged 2.5-5 y at enrollment) with FASDs (n = 60) who received 500 mg choline or a placebo daily for 9 mo. Outcome measures were Mullen Scales of Early Learning (primary) and the elicited imitation (EI) memory paradigm (secondary). RESULTS The administration proved feasible, and choline was well tolerated. Participants received a dose on 88% of enrolled days. The only adverse event linked to choline was a fishy body odor. Choline supplementation improved the secondary outcome (EI) only after immediate recall performance was controlled for, and the outcome was moderated by age. The treatment effect on EI items recalled was significant in the younger participants (2.5- to ≤4.0-y-olds); the young choline group showed an increase of 12-14 percentage points greater than that of the young placebo group on delayed recall measures during treatment. However, there was a marginal baseline difference in delayed item recall between the young choline and placebo groups as well as a potential ceiling effect for item recall, both of which likely contributed to the observed treatment effect. We also observed a trend toward a negative effect of choline supplementation on the immediate EI recall of ordered pairs; the young placebo group showed an increase of 8-17 percentage points greater than that of the choline group during treatment. There was an inverse relation between choline dose (in mg/kg) and memory improvement (P = 0.041); the data suggest that weight-adjusted doses may be a better alternative to a fixed dose in future studies. Limitations included trend-level baseline differences in performance, the post-hoc determination of age moderation, and potential ceiling effects for the memory measure. CONCLUSIONS This pilot study suggests that an additional evaluation of choline supplementation as an intervention for memory functioning in children with FASDs is warranted. The observed interaction between age and cholines effect on EI suggests that potential sensitive periods should be considered in future work. This trial was registered at clinicaltrials.gov as NCT01149538.

A Randomized Trial of Phototherapy with Filtered Sunlight in African Neonates

BACKGROUND Sequelae of severe neonatal hyperbilirubinemia constitute a substantial disease burden in areas where effective conventional phototherapy is unavailable. We previously found that the use of filtered sunlight for the purpose of phototherapy is a safe and efficacious method for reducing total bilirubin. However, its relative safety and efficacy as compared with conventional phototherapy are unknown. METHODS We conducted a randomized, controlled noninferiority trial in which filtered sunlight was compared with conventional phototherapy for the treatment of hyperbilirubinemia in term and late-preterm neonates in a large, urban Nigerian maternity hospital. The primary end point was efficacy, which was defined as a rate of increase in total serum bilirubin of less than 0.2 mg per deciliter per hour for infants up to 72 hours of age or a decrease in total serum bilirubin for infants older than 72 hours of age who received at least 5 hours of phototherapy; we prespecified a noninferiority margin of 10% for the difference in efficacy rates between groups. The need for an exchange transfusion was a secondary end point. We also assessed safety, which was defined as the absence of the need to withdraw therapy because of hyperthermia, hypothermia, dehydration, or sunburn. RESULTS We enrolled 447 infants and randomly assigned 224 to filtered sunlight and 223 to conventional phototherapy. Filtered sunlight was efficacious on 93% of treatment days that could be evaluated, as compared with 90% for conventional phototherapy, and had a higher mean level of irradiance (40 vs. 17 μW per square centimeter per nanometer, P<0.001). Temperatures higher than 38.0°C occurred in 5% of the infants receiving filtered sunlight and in 1% of those receiving conventional phototherapy (P<0.001), but no infant met the criteria for withdrawal from the study for reasons of safety or required an exchange transfusion. CONCLUSIONS Filtered sunlight was noninferior to conventional phototherapy for the treatment of neonatal hyperbilirubinemia and did not result in any study withdrawals for reasons of safety. (Funded by the Thrasher Research Fund, Salt Lake City, and the National Center for Advancing Translational Sciences of the National Institutes of Health; Clinical Trials.gov number, NCT01434810.).

Choline supplementation in children with fetal alcohol spectrum disorders has high feasibility and tolerability.

There are no biological treatments for fetal alcohol spectrum disorders (FASDs), lifelong conditions associated with physical anomalies, brain damage, and neurocognitive abnormalities. In preclinical studies, choline partially ameliorates memory and learning deficits from prenatal alcohol exposure. This phase I pilot study evaluated the feasibility, tolerability, and potential adverse effects of choline supplementation in children with FASD. We hypothesized that choline would be well tolerated with minimal adverse events. The study design was a double-blind, randomized, placebo-controlled trial. Participants included 20 children aged 2.5 to 4.9 years with prenatal alcohol exposure and FASD diagnoses. Participants were randomly assigned to 500 mg choline or placebo daily for 9 months (10 active, 10 placebo). Primary outcome measures included feasibility, tolerability, adverse effects, and serum choline levels. Seventeen participants completed the study. Compliance was 82% to 87%, as evidenced by parent-completed log sheets and dose counts. Periodic 24-hour dietary recalls showed no evidence of dietary confounding. Adverse events were minimal and were equivalent in the active and placebo arms with the exception of fishy body odor, which occurred only in the active group. There were no serious adverse events to research participants. This phase I pilot study demonstrates that choline supplementation at 500 mg/d for 9 months in children aged 2 to 5 years is feasible and has high tolerability. Further examination of the efficacy of choline supplementation in FASD is currently underway.

Safety and Efficacy of Filtered Sunlight in Treatment of Jaundice in African Neonates

OBJECTIVES: Evaluate safety and efficacy of filtered-sunlight phototherapy (FS-PT). METHODS: Term/late preterm infants ≤14 days old with clinically significant jaundice, assessed by total bilirubin (TB) levels, were recruited from a maternity hospital in Lagos, Nigeria. Sunlight was filtered with commercial window-tinting films that remove most UV and significant levels of infrared light and transmit effective levels of therapeutic blue light. After placing infants under an FS-PT canopy, hourly measurements of axillary temperatures, monitoring for sunburn, dehydration, and irradiances of filtered sunlight were performed. Treatment was deemed safe and efficacious if infants were able to stay in FS-PT for ≥5 hours and rate of rise of TB was <0.2 mg/dL/h for infants ≤72 hours of age or TB decreased for infants >72 hours of age. RESULTS: A total of 227 infants received 258 days of FS-PT. No infant developed sunburn or dehydration. On 85 (33%) of 258 treatment days, infants were removed briefly from FS-PT due to minor temperature-related adverse events. No infant met study exit criteria. FS-PT was efficacious in 92% (181/197) of evaluable treatment days. Mean ± SD TB change was –0.06 ± 0.19 mg/dL/h. The mean ± SD (range) irradiance of FS-PT was 38 ± 22 (2–115) µW/cm2/nm, measured by the BiliBlanket Meter II. CONCLUSIONS: With appropriate monitoring, filtered sunlight is a novel, practical, and inexpensive method of PT that potentially offers safe and efficacious treatment strategy for management of neonatal jaundice in tropical countries where conventional PT treatment is not available.

Picosecond time-resolved emission spectra: techniques and examples

Abstract This paper describes a laser spectrometer that yields picosecond time-gated emission spectra which are characterized by a high signal-to-noise ratio and a broad spectral coverage. The crucial experimental methods are presented, with particular emphasis given to the experimental techniques that are necessary to achieve broad spectral coverage. Examples are given of the application of the apparatus in the investigation of the torsional isomerization of 2-vinylanthracene and the transient solvation of electronically excited coumarin 440 in alcoholic solutions.

A pre-post retrospective study of patients with cystic fibrosis and gastrostomy tubes.

Objectives: The aim of the study was to assess the efficacy of gastrostomy tube (GT) placement on improving nutritional status and pulmonary function in patients with cystic fibrosis (CF). Patients and Methods: Data were collected from the Minnesota Cystic Fibrosis Database. Subjects with at least 5 percent-predicted forced expiratory volume in 1 second (ppFEV1) and 1 BMI percentile (pBMI) measurements before and after GT placement were included. Median pBMI values were compared 2 years before and 1, 2, and 4 years after GT placement using a signed rank test. Longitudinal mixed model analysis was used to assess the effect of GT placement on ppFEV1. To assess the effect of ppFEV1 at GT placement on efficacy, the estimated ppFEV1 change was regressed against the ppFEV1 level at placement. Results: Forty-six subjects with CF who met entry criteria were identified. Mean estimated step changes in ppFEV1 at placement for men, women, boys, and girls were 2.16% (P = 0.52), 0.43% (P = 0.92), 0.99% (P = 0.65), and −0.91% (P = 0.74), respectively. Mean estimated slope changes of ppFEV1 after GT placement were 5.01% (P = 0.02), 4.48% (P = 0.07), 1.49% (P = 0.23), and 4.02% (P = 0.01) per year for men, women, boys, and girls, respectively. Median change in pBMI in the second year after GT placement was 13.3% (P ⩽ 0.0001). Estimated coefficients for the effect of ppFEV1 level at placement on the ppFEV1 step and slope change were −0.041 (P = 0.28) and −0.005 (P = 0.84), respectively. Conclusions: GT placement in patients with CF results in significant improvement in both pBMI and ppFEV1, except in women. The change in lung function after GT placement is not dependent on the level of lung function at placement.

Double well isomerization in solution: A new comparison of theory and experiment

The first‐excited‐singlet state of each of the compounds 2‐vinylanthracene (2VA) and 2‐(2’‐propenyl) anthracene (22PA) undergoes an electronically adiabatic torsional double‐well isomerization which interconverts a s‐cis conformation and a s‐trans conformation. The forward rate constant kf for the isomerization was measured by picosecond fluorescence spectroscopy as a function of temperature and solvent viscosity η in the range 0.23–3.25 cP, i.e., in the C5–C16 normal alkanes. For 2VA, kf is independent of η within experimental uncertainty (∼5%), while for 22PA kf≂cη−0.23. An effective torsional isomerization potential of the form V(φ)=(V1/2)(1−cos φ)+(V2/2)(1−cos 2φ) was determined from thermochemical data on the isomerization. Torsional well (ω0) and barrier (ωb) frequencies were calculated from the effective potential and the appropriate moments of inertia. With an estimate in hand for ωb, it was possible to directly evaluate theoretical predications from the (i) theory of Kramers and alternatively fro...